This figure shows the changes in the median age that men and women are when getting married for the first time in the United States from 1890 to 2011.  These data are based on a US Census Bureau table.

For men the age at first marriage declinced slightly from 1890 to 1949 when the age was 22. 7 years of age.  Then it rose slowly until about 1974 and then became to rise more rapidly until today when it is 28.7 years of age in 2011.  Note that cohabitation began to be more more in the 1970s and this may account for some of this change.
For women the age at first marriage declined between 1890 and 1947 when it was 20.3 years of age.  The age at first marriage for women did not change much at all from 1947-1962, then it began to increase until the present where it stands at 26.5 years of age.  This age may also be influenced by increased cohabitation among young people.
For more demographics on marriage and divorce….